Volume of a rectangular box (cuboid) with length = 2ab, breadth = 3 ac and height = 2ac is

⇒ Volume of rectangular box (cuboid) = length× breadth× height

⇒ Volume of rectangular box (cuboid) = 2ab× 3ac× 2ac

⇒ Volume of rectangular box (cuboid) = 12a³bc²

Option (a) does match to our solution.

Option (b) does not match to our solution.

Option (c) does not match to our solution.

Option (d) does not match to our solution.

So, option (a) is correct answer.